{beta}-delayed neutron decay of {sup 19}N and {sup 20}N

Journal Article · Tue Aug 15 00:00:00 EDT 2006 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.74.024322· OSTI ID:20863718

Sumithrarachchi, C S; Anthony, D W; Lofy, P A; Morrissey, D J ^[1]

---

1. National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States) and Department of Chemistry, Michigan State University, East Lansing, Michigan 48824 (United States)

The results of the first spectroscopic studies of delayed neutron and {gamma} emission following the {beta} decay of {sup 19}N and {sup 20}N are reported. Nuclides were produced by fragmenting an 80 MeV/nucleon {sup 22}Ne beam in a 546 mg/cm{sup 2} thick Be target and were separated at high velocities with the A1200 fragment separator. The nuclides were implanted in a thin plastic scintillator at the center of an array of neutron scintillators to determine the neutron time-of-flight spectrum. Two hyperpure germanium detectors were used to observe coincident {gamma} events. The {beta}-{gamma},{beta}-n, and {beta}-n-{gamma} coincidence spectra were analyzed to obtain the energies of the states populated in {sup 18}O, {sup 19}O, and {sup 20}O following the {beta} decay. Eight new neutron energies with a total neutron emission probability of 41.8(9)%, six {gamma} transitions among the excited states of {sup 19}O, and four {gamma} transitions among the excited states of {sup 18}O were identified in the {sup 19}N {beta} decay. Seven new neutron energies with a total neutron emission probability of 42.9(14)%, ten {gamma} transitions among the excited states of {sup 20}O, and two {gamma} transitions among the exited states of {sup 19}O were observed from the {sup 20}N {beta} decay. Half-lives of 336(3) and 136(3) ms were determined for the {sup 19}N and {sup 20}N decays, respectively. The branching ratios of both decays were deduced and compared with USD (universal sd-shell) shell model calculations. The {beta} decay schemes for {sup 19}N and {sup 20}N were de0011duc.

• OSTI ID: 20863718
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 74, Issue 2; Other Information: DOI: 10.1103/PhysRevC.74.024322; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BERYLLIUM 9 TARGET
BETA DECAY
BRANCHING RATIO
DELAYED NEUTRONS
EXCITED STATES
GE SEMICONDUCTOR DETECTORS
HALF-LIFE
MEV RANGE
NEON 22
NEON 22 REACTIONS
NEUTRON EMISSION
NITROGEN 19
NITROGEN 20
OXYGEN 18
OXYGEN 19
OXYGEN 20
PROBABILITY
SHELL MODELS
TIME-OF-FLIGHT METHOD